101
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Causal Shannon-Fisher Characterization of Motor/Imagery Movements in EEG. ENTROPY 2018; 20:e20090660. [PMID: 33265749 PMCID: PMC7513182 DOI: 10.3390/e20090660] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/24/2018] [Revised: 08/30/2018] [Accepted: 08/30/2018] [Indexed: 11/30/2022]
Abstract
The electroencephalogram (EEG) is an electrophysiological monitoring method that allows us to glimpse the electrical activity of the brain. Neural oscillations patterns are perhaps the best salient feature of EEG as they are rhythmic activities of the brain that can be generated by interactions across neurons. Large-scale oscillations can be measured by EEG as the different oscillation patterns reflected within the different frequency bands, and can provide us with new insights into brain functions. In order to understand how information about the rhythmic activity of the brain during visuomotor/imagined cognitive tasks is encoded in the brain we precisely quantify the different features of the oscillatory patterns considering the Shannon–Fisher plane H×F. This allows us to distinguish the dynamics of rhythmic activities of the brain showing that the Beta band facilitate information transmission during visuomotor/imagined tasks.
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102
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Abstract
Art is the ultimate expression of human creativity that is deeply influenced by the philosophy and culture of the corresponding historical epoch. The quantitative analysis of art is therefore essential for better understanding human cultural evolution. Here, we present a large-scale quantitative analysis of almost 140,000 paintings, spanning nearly a millennium of art history. Based on the local spatial patterns in the images of these paintings, we estimate the permutation entropy and the statistical complexity of each painting. These measures map the degree of visual order of artworks into a scale of order-disorder and simplicity-complexity that locally reflects qualitative categories proposed by art historians. The dynamical behavior of these measures reveals a clear temporal evolution of art, marked by transitions that agree with the main historical periods of art. Our research shows that different artistic styles have a distinct average degree of entropy and complexity, thus allowing a hierarchical organization and clustering of styles according to these metrics. We have further verified that the identified groups correspond well with the textual content used to qualitatively describe the styles and the applied complexity-entropy measures can be used for an effective classification of artworks.
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103
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Gavrilov N, Golyagina I, Brazhe A, Scimemi A, Turlapov V, Semyanov A. Astrocytic Coverage of Dendritic Spines, Dendritic Shafts, and Axonal Boutons in Hippocampal Neuropil. Front Cell Neurosci 2018; 12:248. [PMID: 30174590 PMCID: PMC6108058 DOI: 10.3389/fncel.2018.00248] [Citation(s) in RCA: 63] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 07/19/2018] [Indexed: 01/22/2023] Open
Abstract
Distal astrocytic processes have a complex morphology, reminiscent of branchlets and leaflets. Astrocytic branchlets are rod-like processes containing mitochondria and endoplasmic reticulum, capable of generating inositol-3-phosphate (IP3)-dependent Ca2+ signals. Leaflets are small and flat processes that protrude from branchlets and fill the space between synapses. Here we use three-dimensional (3D) reconstructions from serial section electron microscopy (EM) of rat CA1 hippocampal neuropil to determine the astrocytic coverage of dendritic spines, shafts and axonal boutons. The distance to the maximum of the astrocyte volume fraction (VF) correlated with the size of the spine when calculated from the center of mass of the postsynaptic density (PSD) or from the edge of the PSD, but not from the spine surface. This suggests that the astrocytic coverage of small and larger spines is similar in hippocampal neuropil. Diffusion simulations showed that such synaptic microenvironment favors glutamate spillover and extrasynaptic receptor activation at smaller spines. We used complexity and entropy measures to characterize astrocytic branchlets and leaflets. The 2D projections of astrocytic branchlets had smaller spatial complexity and entropy than leaflets, consistent with the higher structural complexity and less organized distribution of leaflets. The VF of astrocytic leaflets was highest around dendritic spines, lower around axonal boutons and lowest around dendritic shafts. In contrast, the VF of astrocytic branchlets was similarly low around these three neuronal compartments. Taken together, these results suggest that astrocytic leaflets preferentially contact synapses as opposed to the dendritic shaft, an arrangement that might favor neurotransmitter spillover and extrasynaptic receptor activation along dendritic shafts.
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Affiliation(s)
- Nikolay Gavrilov
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Inna Golyagina
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alexey Brazhe
- Department of Biophysics, Faculty of Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Annalisa Scimemi
- Department of Biology, University at Albany, The State University of New York (SUNY), Albany, NY, United States
| | - Vadim Turlapov
- Institute of Information Technologies, Mathematics and Mechanics, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alexey Semyanov
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, Nizhny Novgorod, Russia.,Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia.,All-Russian Research Institute of Medicinal and Aromatic Plants, Moscow, Russia
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104
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Brazhe A. Shearlet-based measures of entropy and complexity for two-dimensional patterns. Phys Rev E 2018; 97:061301. [PMID: 30011571 DOI: 10.1103/physreve.97.061301] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Indexed: 11/07/2022]
Abstract
New spatial entropy and complexity measures for two-dimensional patterns are proposed. The approach is based on the notion of disequilibrium and is built on statistics of directional multiscale coefficients of the fast finite shearlet transform. Shannon entropy and Jensen-Shannon divergence measures are employed. Both local and global spatial complexity and entropy estimates can be obtained, thus allowing for spatial mapping of complexity in inhomogeneous patterns. The algorithm is validated in numerical experiments with a gradually decaying periodic pattern and Ising surfaces near critical state. It is concluded that the proposed algorithm can be instrumental in describing a wide range of two-dimensional imaging data, textures, or surfaces, where an understanding of the level of order or randomness is desired.
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Affiliation(s)
- Alexey Brazhe
- Department of Biophysics, Faculty of Biology, Moscow State University, Leninskie gory 1/24, 119234 Russia
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105
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Functional brain networks reveal the existence of cognitive reserve and the interplay between network topology and dynamics. Sci Rep 2018; 8:10525. [PMID: 30002460 PMCID: PMC6043549 DOI: 10.1038/s41598-018-28747-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 05/25/2018] [Indexed: 12/21/2022] Open
Abstract
We investigated how the organization of functional brain networks was related to cognitive reserve (CR) during a memory task in healthy aging. We obtained the magnetoencephalographic functional networks of 20 elders with a high or low CR level to analyse the differences at network features. We reported a negative correlation between synchronization of the whole network and CR, and observed differences both at the node and at the network level in: the average shortest path and the network outreach. Individuals with high CR required functional networks with lower links to successfully carry out the memory task. These results may indicate that those individuals with low CR level exhibited a dual pattern of compensation and network impairment, since their functioning was more energetically costly to perform the task as the high CR group. Additionally, we evaluated how the dynamical properties of the different brain regions were correlated to the network parameters obtaining that entropy was positively correlated with the strength and clustering coefficient, while complexity behaved conversely. Consequently, highly connected nodes of the functional networks showed a more stochastic and less complex signal. We consider that network approach may be a relevant tool to better understand brain functioning in aging.
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106
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Bariviera AF, Zunino L, Rosso OA. An analysis of high-frequency cryptocurrencies prices dynamics using permutation-information-theory quantifiers. CHAOS (WOODBURY, N.Y.) 2018; 28:075511. [PMID: 30070500 DOI: 10.1063/1.5027153] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 06/12/2018] [Indexed: 06/08/2023]
Abstract
This paper discusses the dynamics of intraday prices of 12 cryptocurrencies during the past months' boom and bust. The importance of this study lies in the extended coverage of the cryptoworld, accounting for more than 90% of the total daily turnover. By using the complexity-entropy causality plane, we could discriminate three different dynamics in the data set. Whereas most of the cryptocurrencies follow a similar pattern, there are two currencies (ETC and ETH) that exhibit a more persistent stochastic dynamics, and two other currencies (DASH and XEM) whose behavior is closer to a random walk. Consequently, similar financial assets, using blockchain technology, are differentiated by market participants.
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Affiliation(s)
- Aurelio F Bariviera
- Department of Business, Universitat Rovira i Virgili, Av. Universitat 1, 43204 Reus, Spain
| | - Luciano Zunino
- Centro de Investigaciones Ópticas (CONICET La Plata-CIC), C.C. 3, 1897 Gonnet, Argentina
| | - Osvaldo A Rosso
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires and CONICET, C1199ABB Ciudad Autónoma de Buenos Aires, Argentina
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107
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Legnani W, Traversaro F, Redelico FO, Cymberknop LJ, Armentano RL, Rosso OA. Analysis of ischaemic crisis using the informational causal entropy-complexity plane. CHAOS (WOODBURY, N.Y.) 2018; 28:075518. [PMID: 30070501 DOI: 10.1063/1.5026422] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
In the present work, an ischaemic process, mainly focused on the reperfusion stage, is studied using the informational causal entropy-complexity plane. Ischaemic wall behavior under this condition was analyzed through wall thickness and ventricular pressure variations, acquired during an obstructive flow maneuver performed on left coronary arteries of surgically instrumented animals. Basically, the induction of ischaemia depends on the temporary occlusion of left circumflex coronary artery (which supplies blood to the posterior left ventricular wall) that lasts for a few seconds. Normal perfusion of the wall was then reestablished while the anterior ventricular wall remained adequately perfused during the entire maneuver. The obtained results showed that system dynamics could be effectively described by entropy-complexity loops, in both abnormally and well perfused walls. These results could contribute to making an objective indicator of the recovery heart tissues after an ischaemic process, in a way to quantify the restoration of myocardial behavior after the supply of oxygen to the ventricular wall was suppressed for a brief period.
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Affiliation(s)
- Walter Legnani
- Signal and Image Processing Center (CEPSI), Universidad Tecnológica Nacional, Facultad Regional Buenos Aires, Medrano 951, C1179AAQ Ciudad Autónoma de Buenos Aires, Argentina
| | - Francisco Traversaro
- Grupo de Investigación en Sistemas de Información, Universidad Nacional de Lanús & CONICET, 29 de Septiembre 3901, B1826GLC Lanús, Buenos Aires, Argentina and Instituto Tecnólgico de Buenos Aires (ITBA) & CONICET, Av. Eduardo Madero 399, C1181ACH Ciudad Autónoma de Buenos Aires, Argentina
| | - Francisco O Redelico
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires & CONICET, C1199ABB Ciudad Autónoma de Buenos Aires, Argentina
| | - Leandro J Cymberknop
- Grupo de Investigación y Desarrollo en Bioingeniería (GIBIO and Signal and Image Processing Center (CEPSI), Universidad Tecnológica Nacional, Facultad Regional Buenos Aires, Medrano 951, C1179AAQ Ciudad Autónoma de Buenos Aires, Argentina
| | - Ricardo L Armentano
- Grupo de Investigación y Desarrollo en Bioingeniería (GIBIO and Signal and Image Processing Center (CEPSI), Universidad Tecnológica Nacional, Facultad Regional Buenos Aires, Medrano 951, C1179AAQ Ciudad Autónoma de Buenos Aires, Argentina
| | - Osvaldo A Rosso
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires & CONICET, C1199ABB Ciudad Autónoma de Buenos Aires, Argentina
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108
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Traversaro F, Redelico FO, Risk MR, Frery AC, Rosso OA. Bandt-Pompe symbolization dynamics for time series with tied values: A data-driven approach. CHAOS (WOODBURY, N.Y.) 2018; 28:075502. [PMID: 30070489 DOI: 10.1063/1.5022021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
In 2002, Bandt and Pompe [Phys. Rev. Lett. 88, 174102 (2002)] introduced a successfully symbolic encoding scheme based on the ordinal relation between the amplitude of neighboring values of a given data sequence, from which the permutation entropy can be evaluated. Equalities in the analyzed sequence, for example, repeated equal values, deserve special attention and treatment as was shown recently by Zunino and co-workers [Phys. Lett. A 381, 1883 (2017)]. A significant number of equal values can give rise to false conclusions regarding the underlying temporal structures in practical contexts. In the present contribution, we review the different existing methodologies for treating time series with tied values by classifying them according to their different strategies. In addition, a novel data-driven imputation is presented that proves to outperform the existing methodologies and avoid the false conclusions pointed by Zunino and co-workers.
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Affiliation(s)
- Francisco Traversaro
- Grupo de Investigación en Sistemas de Información, Universidad Nacional de Lanús & CONICET Lanús, 29 de Septiembre 3901, Buenos Aires B1826GLC, Argentina
| | - Francisco O Redelico
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires & CONICET, Ciudad Autónoma de Buenos Aires C1199ABB, Argentina
| | - Marcelo R Risk
- Instituto Tecnólgico de Buenos Aires (ITBA) & CONICET, Av. Eduardo Madero 399, Ciudad Autónoma de Buenos Aires C1181ACH, Argentina
| | - Alejandro C Frery
- Laboratório de Computação Científica e Análise Numérica, Universidade Federal de Alagoas, Av. Lourival Melo Mota, s/n, Maceió, Alagoas 57072-970, Brazil
| | - Osvaldo A Rosso
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires & CONICET, Ciudad Autónoma de Buenos Aires C1199ABB, Argentina
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109
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Baravalle R, Rosso OA, Montani F. Rhythmic activities of the brain: Quantifying the high complexity of beta and gamma oscillations during visuomotor tasks. CHAOS (WOODBURY, N.Y.) 2018; 28:075513. [PMID: 30070505 DOI: 10.1063/1.5025187] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
Electroencephalography (EEG) signals depict the electrical activity that takes place at the surface of the brain and provide an important tool for understanding a variety of cognitive processes. The EEG is the product of synchronized activity of the brain, and variations in EEG oscillations patterns reflect the underlying changes in neuronal synchrony. Our aim is to characterize the complexity of the EEG rhythmic oscillations bands when the subjects perform a visuomotor or imagined cognitive tasks (imagined movement), providing a causal mapping of the dynamical rhythmic activities of the brain as a measure of attentional investment. We estimate the intrinsic correlational structure of the signals within the causality entropy-complexity plane H×C, where the enhanced complexity in the gamma 1, gamma 2, and beta 1 bands allows us to distinguish motor-visual memory tasks from control conditions. We identify the dynamics of the gamma 1, gamma 2, and beta 1 rhythmic oscillations within the zone of a chaotic dissipative behavior, whereas in contrast the beta 2 band shows a much higher level of entropy and a significant low level of complexity that correspond to a non-invertible cubic map. Our findings enhance the importance of the gamma band during attention in perceptual feature binding during the visuomotor/imagery tasks.
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Affiliation(s)
- Roman Baravalle
- IFLYSIB, CONICET & Universidad Nacional de La Plata, Calle 59-789, 1900 La Plata, Argentina
| | - Osvaldo A Rosso
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires & CONICET, C1199ABB Ciudad Autónoma de Buenos Aires, Argentina
| | - Fernando Montani
- IFLYSIB, CONICET & Universidad Nacional de La Plata, Calle 59-789, 1900 La Plata, Argentina
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110
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Plata A, Lebedeva A, Denisov P, Nosova O, Postnikova TY, Pimashkin A, Brazhe A, Zaitsev AV, Rusakov DA, Semyanov A. Astrocytic Atrophy Following Status Epilepticus Parallels Reduced Ca 2+ Activity and Impaired Synaptic Plasticity in the Rat Hippocampus. Front Mol Neurosci 2018; 11:215. [PMID: 29997475 PMCID: PMC6028739 DOI: 10.3389/fnmol.2018.00215] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 05/30/2018] [Indexed: 11/13/2022] Open
Abstract
Epilepsy is a group of neurological disorders commonly associated with the neuronal malfunction leading to generation of seizures. Recent reports point to a possible contribution of astrocytes into this pathology. We used the lithium-pilocarpine model of status epilepticus (SE) in rats to monitor changes in astrocytes. Experiments were performed in acute hippocampal slices 2-4 weeks after SE induction. Nissl staining revealed significant neurodegeneration in the pyramidal cell layers of hippocampal CA1, CA3 areas, and the hilus, but not in the granular cell layer of the dentate gyrus. A significant increase in the density of astrocytes stained with an astrocyte-specific marker, sulforhodamine 101, was observed in CA1 stratum (str.) radiatum. Astrocytes in this area were also whole-cell loaded with a morphological tracer, Alexa Fluor 594, for two-photon excitation imaging. Sholl analyses showed no changes in the size of the astrocytic domain or in the number of primary astrocytic branches, but a significant reduction in the number of distal branches that are resolved with diffraction-limited light microscopy (and are thought to contain Ca2+ stores, such as mitochondria and endoplasmic reticulum). The atrophy of astrocytic branches correlated with the reduced size, but not overall frequency of Ca2+ events. The volume tissue fraction of nanoscopic (beyond the diffraction limit) astrocytic leaflets showed no difference between control and SE animals. The results of spatial entropy-complexity spectrum analysis were also consistent with changes in ratio of astrocytic branches vs. leaflets. In addition, we observed uncoupling of astrocytes through the gap-junctions, which was suggested as a mechanism for reduced K+ buffering. However, no significant difference in time-course of synaptically induced K+ currents in patch-clamped astrocytes argued against possible alterations in K+ clearance by astrocytes. The magnitude of long-term-potentiation (LTP) was reduced after SE. Exogenous D-serine, a co-agonist of NMDA receptors, has rescued the initial phase of LTP. This suggests that the reduced Ca2+-dependent release of D-serine by astrocytes impairs initiation of synaptic plasticity. However, it does not explain the failure of LTP maintenance which may be responsible for cognitive decline associated with epilepsy.
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Affiliation(s)
- Alex Plata
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Albina Lebedeva
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Pavel Denisov
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Olga Nosova
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Tatiana Y. Postnikova
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- Department of Medical Physics, Peter the Great St. Petersburg Polytechnic University, St. Petersburg, Russia
| | - Alexey Pimashkin
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
| | - Alexey Brazhe
- Department of Biophysics, Faculty of Biology, M. V. Lomonosov Moscow State University, Moscow, Russia
| | - Aleksey V. Zaitsev
- Laboratory of Molecular Mechanisms of Neural Interactions, Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
- Institute of Experimental Medicine, Almazov National Medical Research Centre, St. Petersburg, Russia
| | - Dmitri A. Rusakov
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
- UCL Institute of Neurology, University College London, London, United Kingdom
| | - Alexey Semyanov
- UNN Institute of Neuroscience, N. I. Lobachevsky State University of Nizhny Novgorod, University of Nizhny Novgorod, Nizhny Novgorod, Russia
- Department of Molecular Neurobiology, Shemyakin-Ovchinnikov Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
- All-Russian Research Institute of Medicinal and Aromatic Plants, Moscow, Russia
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111
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Aronis KN, Berger RD, Calkins H, Chrispin J, Marine JE, Spragg DD, Tao S, Tandri H, Ashikaga H. Is human atrial fibrillation stochastic or deterministic?-Insights from missing ordinal patterns and causal entropy-complexity plane analysis. CHAOS (WOODBURY, N.Y.) 2018; 28:063130. [PMID: 29960392 PMCID: PMC6026026 DOI: 10.1063/1.5023588] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 06/11/2018] [Indexed: 06/08/2023]
Abstract
The mechanism of atrial fibrillation (AF) maintenance in humans is yet to be determined. It remains controversial whether cardiac fibrillatory dynamics are the result of a deterministic or a stochastic process. Traditional methods to differentiate deterministic from stochastic processes have several limitations and are not reliably applied to short and noisy data obtained during clinical studies. The appearance of missing ordinal patterns (MOPs) using the Bandt-Pompe (BP) symbolization is indicative of deterministic dynamics and is robust to brief time series and experimental noise. Our aim was to evaluate whether human AF dynamics is the result of a stochastic or a deterministic process. We used 38 intracardiac atrial electrograms during AF from the coronary sinus of 10 patients undergoing catheter ablation of AF. We extracted the intervals between consecutive atrial depolarizations (AA interval) and converted the AA interval time series to their BP symbolic representation (embedding dimension 5, time delay 1). We generated 40 iterative amplitude-adjusted, Fourier-transform (IAAFT) surrogate data for each of the AA time series. IAAFT surrogates have the same frequency spectrum, autocorrelation, and probability distribution with the original time series. Using the BP symbolization, we compared the number of MOPs and the rate of MOP decay in the first 1000 timepoints of the original time series with that of the surrogate data. We calculated permutation entropy and permutation statistical complexity and represented each time series on the causal entropy-complexity plane. We demonstrated that (a) the number of MOPs in human AF is significantly higher compared to the surrogate data (2.7 ± 1.18 vs. 0.39 ± 0.28, p < 0.001); (b) the median rate of MOP decay in human AF was significantly lower compared with the surrogate data (6.58 × 10-3 vs. 7.79 × 10-3, p < 0.001); and (c) 81.6% of the individual recordings had a rate of decay lower than the 95% confidence intervals of their corresponding surrogates. On the causal entropy-complexity plane, human AF lay on the deterministic part of the plane that was located above the trajectory of fractional Brownian motion with different Hurst exponents on the plane. This analysis demonstrates that human AF dynamics does not arise from a rescaled linear stochastic process or a fractional noise, but either a deterministic or a nonlinear stochastic process. Our results justify the development and application of mathematical analysis and modeling tools to enable predictive control of human AF.
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Affiliation(s)
- Konstantinos N. Aronis
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Ronald D. Berger
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Hugh Calkins
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Jonathan Chrispin
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Joseph E. Marine
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - David D. Spragg
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Susumu Tao
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Harikrishna Tandri
- Cardiac Arrhythmia Service, Johns Hopkins University School of Medicine, Baltimore, Maryland 21287, USA
| | - Hiroshi Ashikaga
- Author to whom correspondence should be addressed: . Telephone: 410-955-7534. Fax: 443-873-5019
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112
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Wang M, Vilela ALM, Du R, Zhao L, Dong G, Tian L, Stanley HE. Topological properties of the limited penetrable horizontal visibility graph family. Phys Rev E 2018; 97:052117. [PMID: 29906941 DOI: 10.1103/physreve.97.052117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2017] [Indexed: 06/08/2023]
Abstract
The limited penetrable horizontal visibility graph algorithm was recently introduced to map time series in complex networks. In this work, we extend this algorithm to create a directed-limited penetrable horizontal visibility graph and an image-limited penetrable horizontal visibility graph. We define two algorithms and provide theoretical results on the topological properties of these graphs associated with different types of real-value series. We perform several numerical simulations to check the accuracy of our theoretical results. Finally, we present an application of the directed-limited penetrable horizontal visibility graph to measure real-value time series irreversibility and an application of the image-limited penetrable horizontal visibility graph that discriminates noise from chaos. We also propose a method to measure the systematic risk using the image-limited penetrable horizontal visibility graph, and the empirical results show the effectiveness of our proposed algorithms.
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Affiliation(s)
- Minggang Wang
- School of Mathematical Science, Nanjing Normal University, Nanjing 210042, Jiangsu, China
- Department of Mathematics, Nanjing Normal University Taizhou College, Taizhou 225300, Jiangsu, China
- Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA
| | - André L M Vilela
- Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA
- Universidade de Pernambuco, 50100-010, Recife-PE, Brazil
| | - Ruijin Du
- Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA
- Energy Development and Environmental Protection Strategy Research Center, Jiangsu University, Zhenjiang, 212013 Jiangsu, China
| | - Longfeng Zhao
- Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA
| | - Gaogao Dong
- Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA
- Energy Development and Environmental Protection Strategy Research Center, Jiangsu University, Zhenjiang, 212013 Jiangsu, China
| | - Lixin Tian
- School of Mathematical Science, Nanjing Normal University, Nanjing 210042, Jiangsu, China
- Energy Development and Environmental Protection Strategy Research Center, Jiangsu University, Zhenjiang, 212013 Jiangsu, China
| | - H Eugene Stanley
- Center for Polymer Studies and Department of Physics, Boston University, Boston, Massachusetts 02215, USA
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113
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Exact results of the limited penetrable horizontal visibility graph associated to random time series and its application. Sci Rep 2018; 8:5130. [PMID: 29572452 PMCID: PMC5865175 DOI: 10.1038/s41598-018-23388-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 03/12/2018] [Indexed: 11/12/2022] Open
Abstract
The limited penetrable horizontal visibility algorithm is an analysis tool that maps time series into complex networks and is a further development of the horizontal visibility algorithm. This paper presents exact results on the topological properties of the limited penetrable horizontal visibility graph associated with independent and identically distributed (i:i:d:) random series. We show that the i.i.d: random series maps on a limited penetrable horizontal visibility graph with exponential degree distribution, independent of the probability distribution from which the series was generated. We deduce the exact expressions of mean degree and clustering coefficient, demonstrate the long distance visibility property of the graph and perform numerical simulations to test the accuracy of our theoretical results. We then use the algorithm in several deterministic chaotic series, such as the logistic map, H´enon map, Lorenz system, energy price chaotic system and the real crude oil price. Our results show that the limited penetrable horizontal visibility algorithm is efficient to discriminate chaos from uncorrelated randomness and is able to measure the global evolution characteristics of the real time series.
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114
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Kasuya H, Gotoda H, Yoshida S, Tachibana S. Dynamic behavior of combustion instability in a cylindrical combustor with an off-center installed coaxial injector. CHAOS (WOODBURY, N.Y.) 2018; 28:033111. [PMID: 29604630 DOI: 10.1063/1.5025480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
We have intensively studied the dynamic behavior of combustion instability in a cylindrical combustor with an off-center installed coaxial injector. The most interesting discovery in this study is the appearance of a deterministic chaos in a transition from a dynamically stable state to well-developed high-frequency thermoacoustic combustion oscillations with increasing the volume flow rate of nitrogen with which oxygen is diluted. The presence of deterministic chaos is reasonably identified by considering an extended version of the Sugihara-May algorithm [G. Sugihara and R. May, Nature 344, 734 (1990)] as a local predictor and the multiscale complexity-entropy causality plane based on statistical complexity.
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Affiliation(s)
- Haruki Kasuya
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroshi Gotoda
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Seiji Yoshida
- Japan Aerospace Exploration Agency, 7-44-1 Jindaiji-Higashimachi, Chofu-shi, Tokyo 182-8522, Japan
| | - Shigeru Tachibana
- Japan Aerospace Exploration Agency, 7-44-1 Jindaiji-Higashimachi, Chofu-shi, Tokyo 182-8522, Japan
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115
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Antonelli M, De Micco L, Larrondo H, Rosso OA. Complexity of Simple, Switched and Skipped Chaotic Maps in Finite Precision. ENTROPY 2018; 20:e20020135. [PMID: 33265226 PMCID: PMC7512629 DOI: 10.3390/e20020135] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Revised: 02/15/2018] [Accepted: 02/16/2018] [Indexed: 11/18/2022]
Abstract
In this paper we investigate the degradation of the statistic properties of chaotic maps as consequence of their implementation in a digital media such as Digital Signal Processors (DSP), Field Programmable Gate Arrays (FPGA) or Application-Specific Integrated Circuits (ASIC). In these systems, binary floating- and fixed-point are the numerical representations available. Fixed-point representation is preferred over floating-point when speed, low power and/or small circuit area are necessary. Then, in this paper we compare the degradation of fixed-point binary precision version of chaotic maps with the one obtained by using floating point 754-IEEE standard, to evaluate the feasibility of their FPGA implementation. The specific period that every fixed-point precision produces was investigated in previous reports. Statistical characteristics are also relevant, it has been recently shown that it is convenient to describe the statistical characteristic using both, causal and non-causal quantifiers. In this paper we complement the period analysis by characterizing the behavior of these maps from an statistical point of view using cuantifiers from information theory. Here, rather than reproducing an exact replica of the real system, the aim is to meet certain conditions related to the statistics of systems.
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Affiliation(s)
- Maximiliano Antonelli
- Facultad de Ingeniería, Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata B7608FDQ, Argentina
- Instituto de Investigaciones Científicas y Tecnológicas en Electrónica (ICyTE), Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata B7608FDQ, Argentina
- Correspondence: ; Tel.: +54-223-481-6600 (ext. 277)
| | - Luciana De Micco
- Facultad de Ingeniería, Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata B7608FDQ, Argentina
- Instituto de Investigaciones Científicas y Tecnológicas en Electrónica (ICyTE), Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata B7608FDQ, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917, Buenos Aires, Argentina
| | - Hilda Larrondo
- Facultad de Ingeniería, Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata B7608FDQ, Argentina
- Instituto de Investigaciones Científicas y Tecnológicas en Electrónica (ICyTE), Universidad Nacional de Mar del Plata (UNMdP), Mar del Plata B7608FDQ, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917, Buenos Aires, Argentina
| | - Osvaldo Anibal Rosso
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), Rivadavia 1917, Buenos Aires, Argentina
- Departamento de Informática en Salud, Hospital Italiano de Buenos Aires, Ciudad Autónoma de Buenos Aires C1199ABB, Argentina
- Instituto de Física, Universidade Federal de Alagoas (UFAL), Maceió 57072-900, Brazil
- Facultad de Ingeniería y Ciencias Aplicadas, Universidad de Los Andes, Monseñor Álvaro del Portillo 12455, Santiago, Chile
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116
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Faber J, Bozovic D. Chaotic Dynamics of Inner Ear Hair Cells. Sci Rep 2018; 8:3366. [PMID: 29463841 PMCID: PMC5820366 DOI: 10.1038/s41598-018-21538-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Accepted: 02/06/2018] [Indexed: 11/09/2022] Open
Abstract
Experimental records of active bundle motility are used to demonstrate the presence of a low-dimensional chaotic attractor in hair cell dynamics. Dimensionality tests from dynamic systems theory are applied to estimate the number of independent variables sufficient for modelling the hair cell response. Poincaré maps are constructed to observe a quasiperiodic transition from chaos to order with increasing amplitudes of mechanical forcing. The onset of this transition is accompanied by a reduction of Kolmogorov entropy in the system and an increase in transfer entropy between the stimulus and the hair bundle, indicative of signal detection. A simple theoretical model is used to describe the observed chaotic dynamics. The model exhibits an enhancement of sensitivity to weak stimuli when the system is poised in the chaotic regime. We propose that chaos may play a role in the hair cell's ability to detect low-amplitude sounds.
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Affiliation(s)
- Justin Faber
- Department of Physics & Astronomy, University of California, Los Angeles, California, 90095, USA
| | - Dolores Bozovic
- Department of Physics & Astronomy, University of California, Los Angeles, California, 90095, USA. .,California NanoSystems Institute, University of California, Los Angeles, California, 90095, USA.
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117
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Olivares F, Zunino L, Gulich D, Pérez DG, Rosso OA. Multiscale permutation entropy analysis of laser beam wandering in isotropic turbulence. Phys Rev E 2018; 96:042207. [PMID: 29347549 DOI: 10.1103/physreve.96.042207] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Indexed: 11/07/2022]
Abstract
We have experimentally quantified the temporal structural diversity from the coordinate fluctuations of a laser beam propagating through isotropic optical turbulence. The main focus here is on the characterization of the long-range correlations in the wandering of a thin Gaussian laser beam over a screen after propagating through a turbulent medium. To fulfill this goal, a laboratory-controlled experiment was conducted in which coordinate fluctuations of the laser beam were recorded at a sufficiently high sampling rate for a wide range of turbulent conditions. Horizontal and vertical displacements of the laser beam centroid were subsequently analyzed by implementing the symbolic technique based on ordinal patterns to estimate the well-known permutation entropy. We show that the permutation entropy estimations at multiple time scales evidence an interplay between different dynamical behaviors. More specifically, a crossover between two different scaling regimes is observed. We confirm a transition from an integrated stochastic process contaminated with electronic noise to a fractional Brownian motion with a Hurst exponent H=5/6 as the sampling time increases. Besides, we are able to quantify, from the estimated entropy, the amount of electronic noise as a function of the turbulence strength. We have also demonstrated that these experimental observations are in very good agreement with numerical simulations of noisy fractional Brownian motions with a well-defined crossover between two different scaling regimes.
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Affiliation(s)
- Felipe Olivares
- Instituto de Física, Pontificia Universidad Católica de Valparaiso (PUCV), 23-40025 Valparaíso, Chile
| | - Luciano Zunino
- Centro de Investigaciones Ópticas (CONICET La Plata - CIC), C.C. 3, 1897 Gonnet, Argentina.,Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Nacional de La Plata (UNLP), 1900 La Plata, Argentina
| | - Damián Gulich
- Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Nacional de La Plata (UNLP), 1900 La Plata, Argentina.,Instituto de Física de Líquidos y Sistemas Biológicos, CONICET, UNLP, Calle 59 Número 789, 1900 La Plata, Argentina
| | - Darío G Pérez
- Instituto de Física, Pontificia Universidad Católica de Valparaiso (PUCV), 23-40025 Valparaíso, Chile
| | - Osvaldo A Rosso
- Instituto de Física, Universidade Federal de Alagoas (UFAL), BR 104 Norte km 97, 57072-970 Maceió, Alagoas, Brazil.,Departamento de Informática en Salud, Hospital Italiano de Buenos Aires, C1199ABB, Ciudad Autónoma de Buenos Aires, Argentina.,Complex Systems Group, Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Avenida Monseñor Álvaro del Portillo 12.455, Las Condes, Santiago, Chile
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118
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Zhang W, Liu P, Guo H, Wang J. Detecting the chaotic nature in a transitional boundary layer using symbolic information-theory quantifiers. Phys Rev E 2018; 96:052215. [PMID: 29347703 DOI: 10.1103/physreve.96.052215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Indexed: 11/07/2022]
Abstract
The permutation entropy and the statistical complexity are employed to study the boundary-layer transition induced by the surface roughness. The velocity signals measured in the transition process are analyzed with these symbolic quantifiers, as well as the complexity-entropy causality plane, and the chaotic nature of the instability fluctuations is identified. The frequency of the dominant fluctuations has been found according to the time scales corresponding to the extreme values of the symbolic quantifiers. The laminar-turbulent transition process is accompanied by the evolution in the degree of organization of the complex eddy motions, which is also characterized with the growing smaller and flatter circles in the complexity-entropy causality plane. With the help of the permutation entropy and the statistical complexity, the differences between the chaotic fluctuations detected in the experiments and the classical Tollmien-Schlichting wave are shown and discussed. It is also found that the chaotic features of the instability fluctuations can be approximated with a number of regular sine waves superimposed on the fluctuations of the undisturbed laminar boundary layer. This result is related to the physical mechanism in the generation of the instability fluctuations, which is the noise-induced chaos.
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Affiliation(s)
- Wen Zhang
- Key Laboratory of Aero-Acoustics (Beihang University), Ministry of Industry and Information Technology and Key Laboratory of Fluid Mechanics (Beihang University), Ministry of Education, Beijing 100083, People's Republic of China
| | - Peiqing Liu
- Key Laboratory of Aero-Acoustics (Beihang University), Ministry of Industry and Information Technology and Key Laboratory of Fluid Mechanics (Beihang University), Ministry of Education, Beijing 100083, People's Republic of China
| | - Hao Guo
- Key Laboratory of Aero-Acoustics (Beihang University), Ministry of Industry and Information Technology and Key Laboratory of Fluid Mechanics (Beihang University), Ministry of Education, Beijing 100083, People's Republic of China
| | - Jinjun Wang
- Key Laboratory of Aero-Acoustics (Beihang University), Ministry of Industry and Information Technology and Key Laboratory of Fluid Mechanics (Beihang University), Ministry of Education, Beijing 100083, People's Republic of China
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119
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Takagi K, Gotoda H, Tokuda IT, Miyano T. Nonlinear dynamics of a buoyancy-induced turbulent fire. Phys Rev E 2017; 96:052223. [PMID: 29347727 DOI: 10.1103/physreve.96.052223] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Indexed: 11/07/2022]
Abstract
We conduct a numerical study on the dynamic behavior of a buoyancy-induced turbulent fire from the viewpoints of symbolic dynamics, complex networks, and statistical complexity. Here, we consider two classes of entropies: the permutation entropy and network entropy in ε-recurrence networks, both of which evaluate the degree of randomness in the underlying dynamics. These entropies enable us to capture the significant changes in the dynamic behavior of flow velocity fluctuations. The possible presence of two important dynamics, low-dimensional deterministic chaos in the near field dominated by the motion of large-scale vortices and high-dimensional chaos in the far field forming a well-developed turbulent plume, is clearly identified by the multiscale complexity-entropy causality plane.
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Affiliation(s)
- Kazushi Takagi
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroshi Gotoda
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Isao T Tokuda
- Department of Mechanical Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
| | - Takaya Miyano
- Department of Mechanical Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
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120
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Wiedermann M, Donges JF, Kurths J, Donner RV. Mapping and discrimination of networks in the complexity-entropy plane. Phys Rev E 2017; 96:042304. [PMID: 29347608 DOI: 10.1103/physreve.96.042304] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2017] [Indexed: 06/07/2023]
Abstract
Complex networks are usually characterized in terms of their topological, spatial, or information-theoretic properties and combinations of the associated metrics are used to discriminate networks into different classes or categories. However, even with the present variety of characteristics at hand it still remains a subject of current research to appropriately quantify a network's complexity and correspondingly discriminate between different types of complex networks, like infrastructure or social networks, on such a basis. Here we explore the possibility to classify complex networks by means of a statistical complexity measure that has formerly been successfully applied to distinguish different types of chaotic and stochastic time series. It is composed of a network's averaged per-node entropic measure characterizing the network's information content and the associated Jenson-Shannon divergence as a measure of disequilibrium. We study 29 real-world networks and show that networks of the same category tend to cluster in distinct areas of the resulting complexity-entropy plane. We demonstrate that within our framework, connectome networks exhibit among the highest complexity while, e.g., transportation and infrastructure networks display significantly lower values. Furthermore, we demonstrate the utility of our framework by applying it to families of random scale-free and Watts-Strogatz model networks. We then show in a second application that the proposed framework is useful to objectively construct threshold-based networks, such as functional climate networks or recurrence networks, by choosing the threshold such that the statistical network complexity is maximized.
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Affiliation(s)
- Marc Wiedermann
- Potsdam Institute for Climate Impact Research, Telegraphenberg A31, 14473 Potsdam, Germany, EU
- Department of Physics, Humboldt University, Newtonstr. 15, 12489 Berlin, Germany, EU
| | - Jonathan F Donges
- Potsdam Institute for Climate Impact Research, Telegraphenberg A31, 14473 Potsdam, Germany, EU
- Stockholm Resilience Centre, Stockholm University, Kräftriket 2B, 114 19 Stockholm, Sweden, EU
| | - Jürgen Kurths
- Potsdam Institute for Climate Impact Research, Telegraphenberg A31, 14473 Potsdam, Germany, EU
- Department of Physics, Humboldt University, Newtonstr. 15, 12489 Berlin, Germany, EU
| | - Reik V Donner
- Potsdam Institute for Climate Impact Research, Telegraphenberg A31, 14473 Potsdam, Germany, EU
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121
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Characterizing Complexity Changes in Chinese Stock Markets by Permutation Entropy. ENTROPY 2017. [DOI: 10.3390/e19100514] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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122
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Kulp CW, Zunino L, Osborne T, Zawadzki B. Using missing ordinal patterns to detect nonlinearity in time series data. Phys Rev E 2017; 96:022218. [PMID: 28950499 DOI: 10.1103/physreve.96.022218] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2017] [Indexed: 06/07/2023]
Abstract
The number of missing ordinal patterns (NMP) is the number of ordinal patterns that do not appear in a series after it has been symbolized using the Bandt and Pompe methodology. In this paper, the NMP is demonstrated as a test for nonlinearity using a surrogate framework in order to see if the NMP for a series is statistically different from the NMP of iterative amplitude adjusted Fourier transform (IAAFT) surrogates. It is found that the NMP works well as a test statistic for nonlinearity, even in the cases of very short time series. Both model and experimental time series are used to demonstrate the efficacy of the NMP as a test for nonlinearity.
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Affiliation(s)
- Christopher W Kulp
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
| | - Luciano Zunino
- Centro de Investigaciones Ópticas (CONICET La Plata-CIC), C.C. 3, 1897 Gonnet, Argentina and Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Nacional de La Plata (UNLP), 1900 La Plata, Argentina
| | - Thomas Osborne
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
| | - Brianna Zawadzki
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
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123
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Mateos DM, Riveaud LE, Lamberti PW. Detecting dynamical changes in time series by using the Jensen Shannon divergence. CHAOS (WOODBURY, N.Y.) 2017; 27:083118. [PMID: 28863485 DOI: 10.1063/1.4999613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Most of the time series in nature are a mixture of signals with deterministic and random dynamics. Thus the distinction between these two characteristics becomes important. Distinguishing between chaotic and aleatory signals is difficult because they have a common wide band power spectrum, a delta like autocorrelation function, and share other features as well. In general, signals are presented as continuous records and require to be discretized for being analyzed. In this work, we introduce different schemes for discretizing and for detecting dynamical changes in time series. One of the main motivations is to detect transitions between the chaotic and random regime. The tools here used here originate from the Information Theory. The schemes proposed are applied to simulated and real life signals, showing in all cases a high proficiency for detecting changes in the dynamics of the associated time series.
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Affiliation(s)
- D M Mateos
- Neuroscience and Mental Health Programme, Division of Neurology, Hospital for Sick Children, Institute of Medical Science and Department of Paediatrics, University of Toronto, Toronto, Ontario M5G 0A4, Canada
| | - L E Riveaud
- Facultad de Matemática, Astronomía, Física y Computación (FaMAF), Universidad Nacional de Córdoba, CONICET, Córdoba, Argentina
| | - P W Lamberti
- Facultad de Matemática, Astronomía, Física y Computación (FaMAF), Universidad Nacional de Córdoba, CONICET, Córdoba, Argentina
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124
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Ribeiro HV, Jauregui M, Zunino L, Lenzi EK. Characterizing time series via complexity-entropy curves. Phys Rev E 2017; 95:062106. [PMID: 28709196 DOI: 10.1103/physreve.95.062106] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2017] [Indexed: 06/07/2023]
Abstract
The search for patterns in time series is a very common task when dealing with complex systems. This is usually accomplished by employing a complexity measure such as entropies and fractal dimensions. However, such measures usually only capture a single aspect of the system dynamics. Here, we propose a family of complexity measures for time series based on a generalization of the complexity-entropy causality plane. By replacing the Shannon entropy by a monoparametric entropy (Tsallis q entropy) and after considering the proper generalization of the statistical complexity (q complexity), we build up a parametric curve (the q-complexity-entropy curve) that is used for characterizing and classifying time series. Based on simple exact results and numerical simulations of stochastic processes, we show that these curves can distinguish among different long-range, short-range, and oscillating correlated behaviors. Also, we verify that simulated chaotic and stochastic time series can be distinguished based on whether these curves are open or closed. We further test this technique in experimental scenarios related to chaotic laser intensity, stock price, sunspot, and geomagnetic dynamics, confirming its usefulness. Finally, we prove that these curves enhance the automatic classification of time series with long-range correlations and interbeat intervals of healthy subjects and patients with heart disease.
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Affiliation(s)
- Haroldo V Ribeiro
- Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil
| | - Max Jauregui
- Departamento de Física, Universidade Estadual de Maringá, Maringá, PR 87020-900, Brazil
| | - Luciano Zunino
- Centro de Investigaciones Ópticas (CONICET La Plata - CIC), C.C. 3, 1897 Gonnet, Argentina
- Departamento de Ciencias Básicas, Facultad de Ingeniería, Universidad Nacional de La Plata (UNLP), 1900 La Plata, Argentina
| | - Ervin K Lenzi
- Departamento de Física, Universidade Estadual de Ponta Grossa, Ponta Grossa, PR 84030-900, Brazil
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125
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Politi A. Quantifying the Dynamical Complexity of Chaotic Time Series. PHYSICAL REVIEW LETTERS 2017; 118:144101. [PMID: 28430461 DOI: 10.1103/physrevlett.118.144101] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Indexed: 06/07/2023]
Abstract
A powerful approach is proposed for the characterization of chaotic signals. It is based on the combined use of two classes of indicators: (i) the probability of suitable symbolic sequences (obtained from the ordinal patterns of the corresponding time series); (ii) the width of the corresponding cylinder sets. This way, much information can be extracted and used to quantify the complexity of a given signal. As an example of the potentiality of the method, I introduce a modified permutation entropy which allows for quantitative estimates of the Kolmogorov-Sinai entropy in hyperchaotic models, where other methods would be unpractical. As a by-product, estimates of the fractal dimension of the underlying attractors are possible as well.
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Affiliation(s)
- Antonio Politi
- Institute for Complex Systems and Mathematical Biology, SUPA, University of Aberdeen, AB24 3UE, Aberdeen, United Kingdom
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126
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Classification of Normal and Pre-Ictal EEG Signals Using Permutation Entropies and a Generalized Linear Model as a Classifier. ENTROPY 2017. [DOI: 10.3390/e19020072] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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127
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Gotoda H, Kobayashi H, Hayashi K. Chaotic dynamics of a swirling flame front instability generated by a change in gravitational orientation. Phys Rev E 2017; 95:022201. [PMID: 28297884 DOI: 10.1103/physreve.95.022201] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Indexed: 06/06/2023]
Abstract
We have intensively examined the dynamic behavior of flame front instability in a lean swirling premixed flame generated by a change in gravitational orientation [H. Gotoda, T. Miyano, and I. G. Shepherd, Phys. Rev. E 81, 026211 (2010)PLEEE81539-375510.1103/PhysRevE.81.026211] from the viewpoints of complex networks, symbolic dynamics, and statistical complexity. Here, we considered the permutation entropy in combination with the surrogate data method, the permutation spectrum test, and the multiscale complexity-entropy causality plane incorporating a scale-dependent approach, none of which have been considered in the study of flame front instabilities. Our results clearly show the possible presence of chaos in flame front dynamics induced by the coupling of swirl-buoyancy interaction in inverted gravity. The flame front dynamics also possesses a scale-free structure, which is reasonably shown by the probability distribution of the degree in ε-recurrence networks.
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Affiliation(s)
- Hiroshi Gotoda
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Hiroaki Kobayashi
- Department of Mechanical Engineering, Tokyo University of Science, 6-3-1 Niijuku, Katsushika-ku, Tokyo 125-8585, Japan
| | - Kenta Hayashi
- Department of Mechanical Engineering, Ritsumeikan University, 1-1-1 Nojihigashi, Kusatsu, Shiga 525-8577, Japan
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128
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Rosso OA, Ospina R, Frery AC. Classification and Verification of Handwritten Signatures with Time Causal Information Theory Quantifiers. PLoS One 2016; 11:e0166868. [PMID: 27907014 PMCID: PMC5131934 DOI: 10.1371/journal.pone.0166868] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2016] [Accepted: 11/05/2016] [Indexed: 11/19/2022] Open
Abstract
We present a new approach for handwritten signature classification and verification based on descriptors stemming from time causal information theory. The proposal uses the Shannon entropy, the statistical complexity, and the Fisher information evaluated over the Bandt and Pompe symbolization of the horizontal and vertical coordinates of signatures. These six features are easy and fast to compute, and they are the input to an One-Class Support Vector Machine classifier. The results are better than state-of-the-art online techniques that employ higher-dimensional feature spaces which often require specialized software and hardware. We assess the consistency of our proposal with respect to the size of the training sample, and we also use it to classify the signatures into meaningful groups.
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Affiliation(s)
- Osvaldo A. Rosso
- Instituto de Física, Universidade Federal de Alagoas (UFAL), Maceió, AL, Brazil
- Instituto Tecnológico de Buenos Aires (ITBA), and CONICET, Ciudad Autónoma de Buenos Aires, Argentina
- Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Santiago, Chile
- * E-mail:
| | - Raydonal Ospina
- Centro de Ciências Exatas e da Natureza, Departamento de Estatística, Universidade Federal de Pernambuco (UFPE), Recife, PE, Brasil
| | - Alejandro C. Frery
- Laboratório de Computação Científica e Análise Numérica, Universidade Federal de Alagoas (UFAL), Maceió, AL, Brazil
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129
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Bellesia G, Bales BB. Population dynamics, information transfer, and spatial organization in a chemical reaction network under spatial confinement and crowding conditions. Phys Rev E 2016; 94:042306. [PMID: 27841639 DOI: 10.1103/physreve.94.042306] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Indexed: 11/07/2022]
Abstract
We investigate, via Brownian dynamics simulations, the reaction dynamics of a generic, nonlinear chemical network under spatial confinement and crowding conditions. In detail, the Willamowski-Rossler chemical reaction system has been "extended" and considered as a prototype reaction-diffusion system. Our results are potentially relevant to a number of open problems in biophysics and biochemistry, such as the synthesis of primitive cellular units (protocells) and the definition of their role in the chemical origin of life and the characterization of vesicle-mediated drug delivery processes. More generally, the computational approach presented in this work makes the case for the use of spatial stochastic simulation methods for the study of biochemical networks in vivo where the "well-mixed" approximation is invalid and both thermal and intrinsic fluctuations linked to the possible presence of molecular species in low number copies cannot be averaged out.
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Affiliation(s)
- Giovanni Bellesia
- Theoretical Biology and Biophysics Group, Los Alamos National Laboratory, Los Alamos, New Mexico 87545, USA
| | - Benjamin B Bales
- Department of Computer Science, University of California Santa Barbara, Santa Barbara, California 93106, USA
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130
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Zhu S, Gan L. Incomplete phase-space method to reveal time delay from scalar time series. Phys Rev E 2016; 94:052210. [PMID: 27967148 DOI: 10.1103/physreve.94.052210] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Indexed: 11/07/2022]
Abstract
A computationally quick and conceptually simple method to recover time delay of the chaotic system from scalar time series is developed in this paper. We show that the orbits in the incomplete two-dimensional reconstructed phase-space will show local clustering phenomenon after the component reordering procedure proposed in this work. We find that information captured by the incomplete two-dimensional reconstructed phase-space is related to the time delay τ_{0} present in the system, and will be transferred to the reordered component by the procedure of component reordering. We then propose the segmented mean variance (SMV) from the reordered component to identify the time delay τ_{0} of the system. The proposed SMV shows clear maximum when the embedding delay τ of the incomplete reconstruction matches the time delay τ_{0} of the chaotic system. Numerical data generated by a time-delay system based on the Mackey-Glass equation operating in the chaotic regime are used to illustrate the effectiveness of the proposed SMV. Experimental results show that the proposed SMV is robust to additive observational noise and is able to recover the time delay of the chaotic system even though the amount of data is relatively small and the feedback strength is weak. Moreover, the time complexity of the proposed method is quite low.
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Affiliation(s)
- Shengli Zhu
- Center for Cyber Security, School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
| | - Lu Gan
- Center for Cyber Security, School of Electronic Engineering, University of Electronic Science and Technology of China, Chengdu 611731, China
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131
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Lecca P, Mura I, Re A, Barker GC, Ihekwaba AEC. Time Series Analysis of the Bacillus subtilis Sporulation Network Reveals Low Dimensional Chaotic Dynamics. Front Microbiol 2016; 7:1760. [PMID: 27872618 PMCID: PMC5097912 DOI: 10.3389/fmicb.2016.01760] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2016] [Accepted: 10/19/2016] [Indexed: 01/12/2023] Open
Abstract
Chaotic behavior refers to a behavior which, albeit irregular, is generated by an underlying deterministic process. Therefore, a chaotic behavior is potentially controllable. This possibility becomes practically amenable especially when chaos is shown to be low-dimensional, i.e., to be attributable to a small fraction of the total systems components. In this case, indeed, including the major drivers of chaos in a system into the modeling approach allows us to improve predictability of the systems dynamics. Here, we analyzed the numerical simulations of an accurate ordinary differential equation model of the gene network regulating sporulation initiation in Bacillus subtilis to explore whether the non-linearity underlying time series data is due to low-dimensional chaos. Low-dimensional chaos is expectedly common in systems with few degrees of freedom, but rare in systems with many degrees of freedom such as the B. subtilis sporulation network. The estimation of a number of indices, which reflect the chaotic nature of a system, indicates that the dynamics of this network is affected by deterministic chaos. The neat separation between the indices obtained from the time series simulated from the model and those obtained from time series generated by Gaussian white and colored noise confirmed that the B. subtilis sporulation network dynamics is affected by low dimensional chaos rather than by noise. Furthermore, our analysis identifies the principal driver of the networks chaotic dynamics to be sporulation initiation phosphotransferase B (Spo0B). We then analyzed the parameters and the phase space of the system to characterize the instability points of the network dynamics, and, in turn, to identify the ranges of values of Spo0B and of the other drivers of the chaotic dynamics, for which the whole system is highly sensitive to minimal perturbation. In summary, we described an unappreciated source of complexity in the B. subtilis sporulation network by gathering evidence for the chaotic behavior of the system, and by suggesting candidate molecules driving chaos in the system. The results of our chaos analysis can increase our understanding of the intricacies of the regulatory network under analysis, and suggest experimental work to refine our behavior of the mechanisms underlying B. subtilis sporulation initiation control.
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Affiliation(s)
- Paola Lecca
- Department of Mathematics, University of Trento Trento, Italy
| | - Ivan Mura
- Department of Industrial Engineering, Universidad de los Andes Bogotá, Colombia
| | - Angela Re
- Laboratory of Translational Genomics, Centre for Integrative Biology, University of Trento Trento, Italy
| | - Gary C Barker
- Gut Health and Food Safety, Institute of Food Research Norwich, UK
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132
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Sippel S, Lange H, Mahecha MD, Hauhs M, Bodesheim P, Kaminski T, Gans F, Rosso OA. Diagnosing the Dynamics of Observed and Simulated Ecosystem Gross Primary Productivity with Time Causal Information Theory Quantifiers. PLoS One 2016; 11:e0164960. [PMID: 27764187 PMCID: PMC5072746 DOI: 10.1371/journal.pone.0164960] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2016] [Accepted: 10/04/2016] [Indexed: 12/01/2022] Open
Abstract
Data analysis and model-data comparisons in the environmental sciences require diagnostic measures that quantify time series dynamics and structure, and are robust to noise in observational data. This paper investigates the temporal dynamics of environmental time series using measures quantifying their information content and complexity. The measures are used to classify natural processes on one hand, and to compare models with observations on the other. The present analysis focuses on the global carbon cycle as an area of research in which model-data integration and comparisons are key to improving our understanding of natural phenomena. We investigate the dynamics of observed and simulated time series of Gross Primary Productivity (GPP), a key variable in terrestrial ecosystems that quantifies ecosystem carbon uptake. However, the dynamics, patterns and magnitudes of GPP time series, both observed and simulated, vary substantially on different temporal and spatial scales. We demonstrate here that information content and complexity, or Information Theory Quantifiers (ITQ) for short, serve as robust and efficient data-analytical and model benchmarking tools for evaluating the temporal structure and dynamical properties of simulated or observed time series at various spatial scales. At continental scale, we compare GPP time series simulated with two models and an observations-based product. This analysis reveals qualitative differences between model evaluation based on ITQ compared to traditional model performance metrics, indicating that good model performance in terms of absolute or relative error does not imply that the dynamics of the observations is captured well. Furthermore, we show, using an ensemble of site-scale measurements obtained from the FLUXNET archive in the Mediterranean, that model-data or model-model mismatches as indicated by ITQ can be attributed to and interpreted as differences in the temporal structure of the respective ecological time series. At global scale, our understanding of C fluxes relies on the use of consistently applied land models. Here, we use ITQ to evaluate model structure: The measures are largely insensitive to climatic scenarios, land use and atmospheric gas concentrations used to drive them, but clearly separate the structure of 13 different land models taken from the CMIP5 archive and an observations-based product. In conclusion, diagnostic measures of this kind provide data-analytical tools that distinguish different types of natural processes based solely on their dynamics, and are thus highly suitable for environmental science applications such as model structural diagnostics.
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Affiliation(s)
| | - Holger Lange
- Norwegian Institute of Bioeconomy Research, Ås, Norway
- Instituto de Física, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Miguel D. Mahecha
- Max Planck Institute for Biogeochemistry, Jena, Germany
- German Centre for Integrative Biodiversity Research (iDiv), Leipzig, Germany
- Michael Stifel Center Jena for Data-Driven and Simulation Science, Jena, Germany
| | | | | | | | - Fabian Gans
- Max Planck Institute for Biogeochemistry, Jena, Germany
| | - Osvaldo A. Rosso
- Instituto de Física, Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
- Instituto Tecnológico de Buenos Aires (ITBA) and CONICET, Ciudad Autónoma de Buenos Aires, Argentina
- Complex Systems Group, Facultad de Ingeniería y Ciencias Aplicadas, Universidad de los Andes, Las Condes, Santiago, Chile
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133
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Gérard A, Yapu-Quispe L, Sakuma S, Ghezzi F, Ramírez-Ávila GM. Nonlinear behavior of the tarka flute's distinctive sounds. CHAOS (WOODBURY, N.Y.) 2016; 26:093114. [PMID: 27781455 DOI: 10.1063/1.4962916] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The Andean tarka flute generates multiphonic sounds. Using spectral techniques, we verify two distinctive musical behaviors and the nonlinear nature of the tarka. Through nonlinear time series analysis, we determine chaotic and hyperchaotic behavior. Experimentally, we observe that by increasing the blow pressure on different fingerings, peculiar changes from linear to nonlinear patterns are produced, leading ultimately to quenching.
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Affiliation(s)
- Arnaud Gérard
- Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, Casilla 8635, La Paz, Bolivia
| | - Luis Yapu-Quispe
- Instituto de Matemática e Estatística, Universidade Federal Fluminense, Nitéroi, Brazil
| | | | - Flavio Ghezzi
- Instituto de Investigaciones Físicas, Universidad Mayor de San Andrés, Casilla 8635, La Paz, Bolivia
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134
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Reinoso JA, Torrent MC, Masoller C. Emergence of spike correlations in periodically forced excitable systems. Phys Rev E 2016; 94:032218. [PMID: 27739791 DOI: 10.1103/physreve.94.032218] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2015] [Indexed: 06/06/2023]
Abstract
In sensory neurons the presence of noise can facilitate the detection of weak information-carrying signals, which are encoded and transmitted via correlated sequences of spikes. Here we investigate the relative temporal order in spike sequences induced by a subthreshold periodic input in the presence of white Gaussian noise. To simulate the spikes, we use the FitzHugh-Nagumo model and to investigate the output sequence of interspike intervals (ISIs), we use the symbolic method of ordinal analysis. We find different types of relative temporal order in the form of preferred ordinal patterns that depend on both the strength of the noise and the period of the input signal. We also demonstrate a resonancelike behavior, as certain periods and noise levels enhance temporal ordering in the ISI sequence, maximizing the probability of the preferred patterns. Our findings could be relevant for understanding the mechanisms underlying temporal coding, by which single sensory neurons represent in spike sequences the information about weak periodic stimuli.
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Affiliation(s)
- José A Reinoso
- Departament de Fisica, Universitat Politecnica de Catalunya, Colom 11, ES-08222 Terrassa, Barcelona, Spain
| | - M C Torrent
- Departament de Fisica, Universitat Politecnica de Catalunya, Colom 11, ES-08222 Terrassa, Barcelona, Spain
| | - Cristina Masoller
- Departament de Fisica, Universitat Politecnica de Catalunya, Colom 11, ES-08222 Terrassa, Barcelona, Spain
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135
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A Complexity-Based Approach for the Detection of Weak Signals in Ocean Ambient Noise. ENTROPY 2016. [DOI: 10.3390/e18030101] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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136
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Yang YG, Zhao QQ. Novel pseudo-random number generator based on quantum random walks. Sci Rep 2016; 6:20362. [PMID: 26842402 PMCID: PMC4740897 DOI: 10.1038/srep20362] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2015] [Accepted: 10/14/2015] [Indexed: 11/23/2022] Open
Abstract
In this paper, we investigate the potential application of quantum computation for constructing pseudo-random number generators (PRNGs) and further construct a novel PRNG based on quantum random walks (QRWs), a famous quantum computation model. The PRNG merely relies on the equations used in the QRWs, and thus the generation algorithm is simple and the computation speed is fast. The proposed PRNG is subjected to statistical tests such as NIST and successfully passed the test. Compared with the representative PRNG based on quantum chaotic maps (QCM), the present QRWs-based PRNG has some advantages such as better statistical complexity and recurrence. For example, the normalized Shannon entropy and the statistical complexity of the QRWs-based PRNG are 0.999699456771172 and 1.799961178212329e-04 respectively given the number of 8 bits-words, say, 16Mbits. By contrast, the corresponding values of the QCM-based PRNG are 0.999448131481064 and 3.701210794388818e-04 respectively. Thus the statistical complexity and the normalized entropy of the QRWs-based PRNG are closer to 0 and 1 respectively than those of the QCM-based PRNG when the number of words of the analyzed sequence increases. It provides a new clue to construct PRNGs and also extends the applications of quantum computation.
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Affiliation(s)
- Yu-Guang Yang
- College of Computer Science and Technology, Beijing University of Technology, Beijing, 100124, China
- State Key Laboratory of Information Security (Institute of Information Engineering, Chinese Academy of Sciences, Beijing, 100093), China
- Beijing Key Laboratory of Trusted Computing, Beijing, 100124, China
- National Engineering Laboratory for Critical Technologies of Information Security Classified Protection, Beijing, 100124, China
| | - Qian-Qian Zhao
- College of Computer Science and Technology, Beijing University of Technology, Beijing, 100124, China
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137
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Gekelman W, Pribyl P, Lucky Z, Drandell M, Leneman D, Maggs J, Vincena S, Van Compernolle B, Tripathi SKP, Morales G, Carter TA, Wang Y, DeHaas T. The upgraded Large Plasma Device, a machine for studying frontier basic plasma physics. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2016; 87:025105. [PMID: 26931889 DOI: 10.1063/1.4941079] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 01/10/2016] [Indexed: 06/05/2023]
Abstract
In 1991 a manuscript describing an instrument for studying magnetized plasmas was published in this journal. The Large Plasma Device (LAPD) was upgraded in 2001 and has become a national user facility for the study of basic plasma physics. The upgrade as well as diagnostics introduced since then has significantly changed the capabilities of the device. All references to the machine still quote the original RSI paper, which at this time is not appropriate. In this work, the properties of the updated LAPD are presented. The strategy of the machine construction, the available diagnostics, the parameters available for experiments, as well as illustrations of several experiments are presented here.
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Affiliation(s)
- W Gekelman
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - P Pribyl
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - Z Lucky
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - M Drandell
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - D Leneman
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - J Maggs
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - S Vincena
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - B Van Compernolle
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - S K P Tripathi
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - G Morales
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - T A Carter
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - Y Wang
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
| | - T DeHaas
- Department of Physics and Astronomy, University of California, Los Angeles, California 90095, USA and Institute of Geophysics and Planetary Physics, University of California, Los Angeles, California 90095, USA
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138
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Kulp CW, Chobot JM, Niskala BJ, Needhammer CJ. Using forbidden ordinal patterns to detect determinism in irregularly sampled time series. CHAOS (WOODBURY, N.Y.) 2016; 26:023107. [PMID: 26931588 DOI: 10.1063/1.4941674] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
It is known that when symbolizing a time series into ordinal patterns using the Bandt-Pompe (BP) methodology, there will be ordinal patterns called forbidden patterns that do not occur in a deterministic series. The existence of forbidden patterns can be used to identify deterministic dynamics. In this paper, the ability to use forbidden patterns to detect determinism in irregularly sampled time series is tested on data generated from a continuous model system. The study is done in three parts. First, the effects of sampling time on the number of forbidden patterns are studied on regularly sampled time series. The next two parts focus on two types of irregular-sampling, missing data and timing jitter. It is shown that forbidden patterns can be used to detect determinism in irregularly sampled time series for low degrees of sampling irregularity (as defined in the paper). In addition, comments are made about the appropriateness of using the BP methodology to symbolize irregularly sampled time series.
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Affiliation(s)
- C W Kulp
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
| | - J M Chobot
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
| | - B J Niskala
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
| | - C J Needhammer
- The Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
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139
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Yang YG, Xu P, Yang R, Zhou YH, Shi WM. Quantum Hash function and its application to privacy amplification in quantum key distribution, pseudo-random number generation and image encryption. Sci Rep 2016; 6:19788. [PMID: 26823196 PMCID: PMC4731770 DOI: 10.1038/srep19788] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 11/02/2015] [Indexed: 11/16/2022] Open
Abstract
Quantum information and quantum computation have achieved a huge success during the last years. In this paper, we investigate the capability of quantum Hash function, which can be constructed by subtly modifying quantum walks, a famous quantum computation model. It is found that quantum Hash function can act as a hash function for the privacy amplification process of quantum key distribution systems with higher security. As a byproduct, quantum Hash function can also be used for pseudo-random number generation due to its inherent chaotic dynamics. Further we discuss the application of quantum Hash function to image encryption and propose a novel image encryption algorithm. Numerical simulations and performance comparisons show that quantum Hash function is eligible for privacy amplification in quantum key distribution, pseudo-random number generation and image encryption in terms of various hash tests and randomness tests. It extends the scope of application of quantum computation and quantum information.
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Affiliation(s)
- Yu-Guang Yang
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
- State Key Laboratory of Information Security (Institute of Information Engineering, Chinese Academy of Sciences, Beijing 100093, China
- Beijing Key Laboratory of Trusted Computing, Beijing 100124, China
- National Engineering Laboratory for Critical Technologies of Information Security Classified Protection, Beijing 100124, China
| | - Peng Xu
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
| | - Rui Yang
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
| | - Yi-Hua Zhou
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
| | - Wei-Min Shi
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
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140
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Montani F, Rosso OA, Matias FS, Bressler SL, Mirasso CR. A symbolic information approach to determine anticipated and delayed synchronization in neuronal circuit models. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2015.0110. [PMID: 26527818 DOI: 10.1098/rsta.2015.0110] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/28/2015] [Indexed: 06/05/2023]
Abstract
The phenomenon of synchronization between two or more areas of the brain coupled asymmetrically is a relevant issue for understanding mechanisms and functions within the cerebral cortex. Anticipated synchronization (AS) refers to the situation in which the receiver system synchronizes to the future dynamics of the sender system while the intuitively expected delayed synchronization (DS) represents exactly the opposite case. AS and DS are investigated in the context of causal information formalism. More specifically, we use a multi-scale symbolic information-theory approach for discriminating the time delay displayed between two areas of the brain when they exchange information.
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Affiliation(s)
- Fernando Montani
- Instituto de Física de Líquidos y Sistemas Biológicos (IFLYSIB), CONICET and Universidad Nacional de La Plata, Calle 59-789, La Plata 1900, Argentina
| | - Osvaldo A Rosso
- Instituto Tecnológico de Buenos Aires (ITBA), Av Eduardo Madero 399, Ciudad Autónoma de Buenos Aires C1106ACD, Argentina Instituto de Física, Universidade Federal de Alagoas (UFAL), BR 104 Norte km 97, Maceió, Alagoas 57072-970, Brazil
| | - Fernanda S Matias
- Instituto de Física, Universidade Federal de Alagoas (UFAL), BR 104 Norte km 97, Maceió, Alagoas 57072-970, Brazil
| | - Steven L Bressler
- Center for Complex Systems and Brain Sciences, Department of Psychology, Florida Atlantic University, Boca Raton, FL 33431, USA
| | - Claudio R Mirasso
- Instituto de Física Interdisciplinary Sistemas Complejos (IFISC, CSIC-UIB), Campus Universitat de les Illes Balears, Palma de Mallorca 07122, Spain
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141
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Montani F, Baravalle R, Montangie L, Rosso OA. Causal information quantification of prominent dynamical features of biological neurons. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2015.0109. [PMID: 26527819 DOI: 10.1098/rsta.2015.0109] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/21/2015] [Indexed: 06/05/2023]
Abstract
Neurons tend to fire a spike when they are near a bifurcation from the resting state to spiking activity. It is a delicate balance between noise, dynamic currents and initial condition that determines the phase diagram of neural activity. Many possible ionic mechanisms can be accounted for as the source of spike generation. Moreover, the biophysics and the dynamics behind it can usually be described through a phase diagram that involves membrane voltage versus the activation variable of the ionic channel. In this paper, we present a novel methodology to characterize the dynamics of this system, which takes into account the fine temporal 'structures' of the complex neuronal signals. This allows us to accurately distinguish the most fundamental properties of neurophysiological neurons that were previously described by Izhikevich considering the phase-space trajectory, using a time causal space: statistical complexity versus Fisher information versus Shannon entropy.
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Affiliation(s)
- Fernando Montani
- Instituto de Física de Líquidos y Sistemas Biológicos (IFLYSIB), CONICET, and Universidad Nacional de La Plata, Calle 59-789, La Plata 1900, Argentina
| | - Roman Baravalle
- Instituto de Física de Líquidos y Sistemas Biológicos (IFLYSIB), CONICET, and Universidad Nacional de La Plata, Calle 59-789, La Plata 1900, Argentina
| | - Lisandro Montangie
- Instituto de Física de Líquidos y Sistemas Biológicos (IFLYSIB), CONICET, and Universidad Nacional de La Plata, Calle 59-789, La Plata 1900, Argentina
| | - Osvaldo A Rosso
- Instituto Tecnológico de Buenos Aires (ITBA), Av Eduardo Madero 399, C1106ACD Ciudad Autónoma de Buenos Aires, Argentina Instituto de Física, Universidade Federal de Alagoas (UFAL), BR 104 Norte km 97, 57072-970 Maceió, Alagoas, Brazil
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142
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Bariviera AF, Guercio MB, Martinez LB, Rosso OA. A permutation information theory tour through different interest rate maturities: the Libor case. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2015; 373:rsta.2015.0119. [PMID: 26527817 DOI: 10.1098/rsta.2015.0119] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/20/2015] [Indexed: 06/05/2023]
Abstract
This paper analyses Libor interest rates for seven different maturities and referred to operations in British pounds, euros, Swiss francs and Japanese yen, during the period 2001-2015. The analysis is performed by means of two quantifiers derived from information theory: the permutation Shannon entropy and the permutation Fisher information measure. An anomalous behaviour in the Libor is detected in all currencies except euros during the years 2006-2012. The stochastic switch is more severe in one, two and three months maturities. Given the special mechanism of Libor setting, we conjecture that the behaviour could have been produced by the manipulation that was uncovered by financial authorities. We argue that our methodology is pertinent as a market overseeing instrument.
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Affiliation(s)
| | - María Belén Guercio
- Instituto de Investigaciones Económicas y Sociales del Sur, Universidad Nacional del Sur (UNS), 12 de Octubre y San Juan, Bahía Blanca B8000CTX, Argentina Universidad Provincial de Sudoeste, Alvarado 332, Bahía Blanca B8000CJH, Argentina
| | - Lisana B Martinez
- Instituto de Investigaciones Económicas y Sociales del Sur, Universidad Nacional del Sur (UNS), 12 de Octubre y San Juan, Bahía Blanca B8000CTX, Argentina Universidad Provincial de Sudoeste, Alvarado 332, Bahía Blanca B8000CJH, Argentina
| | - Osvaldo A Rosso
- Instituto Tecnológico de Buenos Aires (ITBA), Av. Eduardo Madero 399, Ciudad Autónoma de Buenos Aires C1106ACD, Argentina Instituto de Física, Universidade Federal de Alagoas (UFAL), BR 104 Norte km 97, Maceió, Alagoas 57072-970, Brazil
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143
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Subramaniyam NP, Donges JF, Hyttinen J. Signatures of chaotic and stochastic dynamics uncovered with
ε
-recurrence networks. Proc Math Phys Eng Sci 2015. [DOI: 10.1098/rspa.2015.0349] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
An old and important problem in the field of nonlinear time-series analysis entails the distinction between chaotic and stochastic dynamics. Recently,
ε
-recurrence networks have been proposed as a tool to analyse the structural properties of a time series. In this paper, we propose the applicability of local and global
ε
-recurrence network measures to distinguish between chaotic and stochastic dynamics using paradigmatic model systems such as the Lorenz system, and the chaotic and hyper-chaotic Rössler system. We also demonstrate the effect of increasing levels of noise on these network measures and provide a real-world application of analysing electroencephalographic data comprising epileptic seizures. Our results show that both local and global
ε
-recurrence network measures are sensitive to the presence of unstable periodic orbits and other structural features associated with chaotic dynamics that are otherwise absent in stochastic dynamics. These network measures are still robust at high noise levels and short data lengths. Furthermore,
ε
-recurrence network analysis of the real-world epileptic data revealed the capability of these network measures in capturing dynamical transitions using short window sizes.
ε
-recurrence network analysis is a powerful method in uncovering the signatures of chaotic and stochastic dynamics based on the geometrical properties of time series.
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Affiliation(s)
- N. P. Subramaniyam
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- BioMediTech, Tampere, Finland
| | - J. F. Donges
- Earth System Analysis, Potsdam Institute for Climate Impact Research, Potsdam, Germany
- Planetary Boundary Research Lab, Stockholm University, Stockholm, Sweden
| | - J. Hyttinen
- Department of Electronics and Communications Engineering, Tampere University of Technology, Tampere, Finland
- BioMediTech, Tampere, Finland
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144
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Li Q, Fu Z, Yuan N. Beyond Benford's Law: Distinguishing Noise from Chaos. PLoS One 2015; 10:e0129161. [PMID: 26030809 PMCID: PMC4452586 DOI: 10.1371/journal.pone.0129161] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 05/05/2015] [Indexed: 11/24/2022] Open
Abstract
Determinism and randomness are two inherent aspects of all physical processes. Time series from chaotic systems share several features identical with those generated from stochastic processes, which makes them almost undistinguishable. In this paper, a new method based on Benford's law is designed in order to distinguish noise from chaos by only information from the first digit of considered series. By applying this method to discrete data, we confirm that chaotic data indeed can be distinguished from noise data, quantitatively and clearly.
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Affiliation(s)
- Qinglei Li
- Laboratory for Climate and Ocean-Atmosphere Studies, Dept. of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
| | - Zuntao Fu
- Laboratory for Climate and Ocean-Atmosphere Studies, Dept. of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
- * E-mail: (ZTF); (NMY)
| | - Naiming Yuan
- Laboratory for Climate and Ocean-Atmosphere Studies, Dept. of Atmospheric and Oceanic Sciences, School of Physics, Peking University, Beijing, China
- Department of Geography, Climatology, Climate Dynamics, and Climate Change, Justus-Liebig University Giessen, Giessen, Germany
- * E-mail: (ZTF); (NMY)
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145
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Nakajima K, Schmidt N, Pfeifer R. Measuring information transfer in a soft robotic arm. BIOINSPIRATION & BIOMIMETICS 2015; 10:035007. [PMID: 25970447 DOI: 10.1088/1748-3190/10/3/035007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Soft robots can exhibit diverse behaviors with simple types of actuation by partially outsourcing control to the morphological and material properties of their soft bodies, which is made possible by the tight coupling between control, body, and environment. In this paper, we present a method that will quantitatively characterize these diverse spatiotemporal dynamics of a soft body based on the information-theoretic approach. In particular, soft bodies have the ability to propagate the effect of actuation through the entire body, with a certain time delay, due to their elasticity. Our goal is to capture this delayed interaction in a quantitative manner based on a measure called momentary information transfer. We extend this measure to soft robotic applications and demonstrate its power using a physical soft robotic platform inspired by the octopus. Our approach is illustrated in two ways. First, we statistically characterize the delayed actuation propagation through the body as a strength of information transfer. Second, we capture this information propagation directly as local information dynamics. As a result, we show that our approach can successfully characterize the spatiotemporal dynamics of the soft robotic platform, explicitly visualizing how information transfers through the entire body with delays. Further extension scenarios of our approach are discussed for soft robotic applications in general.
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Affiliation(s)
- K Nakajima
- The Hakubi Center for Advanced Research, Kyoto University, 606-8501 Kyoto, Japan. Department of Applied Analysis and Complex Dynamical Systems, Graduate School of Informatics, Kyoto University, 606-8501 Kyoto, Japan
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146
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Rosso OA, Olivares F, Plastino A. Noise versus chaos in a causal Fisher-Shannon plane. PAPERS IN PHYSICS 2015. [DOI: 10.4279/pip.070006] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
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147
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Weck PJ, Schaffner DA, Brown MR, Wicks RT. Permutation entropy and statistical complexity analysis of turbulence in laboratory plasmas and the solar wind. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 91:023101. [PMID: 25768612 DOI: 10.1103/physreve.91.023101] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2014] [Indexed: 06/04/2023]
Abstract
The Bandt-Pompe permutation entropy and the Jensen-Shannon statistical complexity are used to analyze fluctuating time series of three different turbulent plasmas: the magnetohydrodynamic (MHD) turbulence in the plasma wind tunnel of the Swarthmore Spheromak Experiment (SSX), drift-wave turbulence of ion saturation current fluctuations in the edge of the Large Plasma Device (LAPD), and fully developed turbulent magnetic fluctuations of the solar wind taken from the Wind spacecraft. The entropy and complexity values are presented as coordinates on the CH plane for comparison among the different plasma environments and other fluctuation models. The solar wind is found to have the highest permutation entropy and lowest statistical complexity of the three data sets analyzed. Both laboratory data sets have larger values of statistical complexity, suggesting that these systems have fewer degrees of freedom in their fluctuations, with SSX magnetic fluctuations having slightly less complexity than the LAPD edge I(sat). The CH plane coordinates are compared to the shape and distribution of a spectral decomposition of the wave forms. These results suggest that fully developed turbulence (solar wind) occupies the lower-right region of the CH plane, and that other plasma systems considered to be turbulent have less permutation entropy and more statistical complexity. This paper presents use of this statistical analysis tool on solar wind plasma, as well as on an MHD turbulent experimental plasma.
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Affiliation(s)
- P J Weck
- Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - D A Schaffner
- Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - M R Brown
- Swarthmore College, Swarthmore, Pennsylvania 19081, USA
| | - R T Wicks
- NASA Goddard Space Flight Center, Greenbelt, Maryland 20771, USA
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148
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Yang YG, Pan QX, Sun SJ, Xu P. Novel image encryption based on quantum walks. Sci Rep 2015; 5:7784. [PMID: 25586889 PMCID: PMC4293593 DOI: 10.1038/srep07784] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Accepted: 12/15/2014] [Indexed: 11/09/2022] Open
Abstract
Quantum computation has achieved a tremendous success during the last decades. In this paper, we investigate the potential application of a famous quantum computation model, i.e., quantum walks (QW) in image encryption. It is found that QW can serve as an excellent key generator thanks to its inherent nonlinear chaotic dynamic behavior. Furthermore, we construct a novel QW-based image encryption algorithm. Simulations and performance comparisons show that the proposal is secure enough for image encryption and outperforms prior works. It also opens the door towards introducing quantum computation into image encryption and promotes the convergence between quantum computation and image processing.
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Affiliation(s)
- Yu-Guang Yang
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
- State Key Laboratory of Information Security (Institute of Information Engineering, Chinese Academy of Sciences, Beijing 100093)
| | - Qing-Xiang Pan
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
| | - Si-Jia Sun
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
| | - Peng Xu
- College of Computer Science and Technology, Beijing University of Technology, Beijing 100124, China
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149
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Ravetti MG, Carpi LC, Gonçalves BA, Frery AC, Rosso OA. Distinguishing noise from chaos: objective versus subjective criteria using horizontal visibility graph. PLoS One 2014; 9:e108004. [PMID: 25247303 PMCID: PMC4172653 DOI: 10.1371/journal.pone.0108004] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2013] [Accepted: 08/11/2014] [Indexed: 12/03/2022] Open
Abstract
A recently proposed methodology called the Horizontal Visibility Graph (HVG) [Luque et al., Phys. Rev. E., 80, 046103 (2009)] that constitutes a geometrical simplification of the well known Visibility Graph algorithm [Lacasa et al., Proc. Natl. Sci. U.S.A. 105, 4972 (2008)], has been used to study the distinction between deterministic and stochastic components in time series [L. Lacasa and R. Toral, Phys. Rev. E., 82, 036120 (2010)]. Specifically, the authors propose that the node degree distribution of these processes follows an exponential functional of the form [Formula: see text], in which [Formula: see text] is the node degree and [Formula: see text] is a positive parameter able to distinguish between deterministic (chaotic) and stochastic (uncorrelated and correlated) dynamics. In this work, we investigate the characteristics of the node degree distributions constructed by using HVG, for time series corresponding to [Formula: see text] chaotic maps, 2 chaotic flows and [Formula: see text] different stochastic processes. We thoroughly study the methodology proposed by Lacasa and Toral finding several cases for which their hypothesis is not valid. We propose a methodology that uses the HVG together with Information Theory quantifiers. An extensive and careful analysis of the node degree distributions obtained by applying HVG allow us to conclude that the Fisher-Shannon information plane is a remarkable tool able to graphically represent the different nature, deterministic or stochastic, of the systems under study.
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Affiliation(s)
- Martín Gómez Ravetti
- Departamento de Engenharia de Produção, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Departament de Física Fonamental, Universitat de Barcelona, Barcelona, Spain
| | - Laura C. Carpi
- Laboratório de Computação Científica e Análise Numérica (LaCCAN), Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Bruna Amin Gonçalves
- Departamento de Engenharia de Produção, Universidade Federal de Minas Gerais, Belo Horizonte, Minas Gerais, Brazil
- Instituto Politécnico. Centro Universitário UNA, Belo Horizonte, Minas Gerais, Brazil
| | - Alejandro C. Frery
- Laboratório de Computação Científica e Análise Numérica (LaCCAN), Universidade Federal de Alagoas, Maceió, Alagoas, Brazil
| | - Osvaldo A. Rosso
- Instituto de Física, Universidade Federal de Alagoas, Maceió, Alagoas – Brazil
- Instituto Tecnológico de Buenos Aires (ITBA), Ciudad Autónoma de Buenos Aires, Argentina
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150
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Kulp CW, Zunino L. Discriminating chaotic and stochastic dynamics through the permutation spectrum test. CHAOS (WOODBURY, N.Y.) 2014; 24:033116. [PMID: 25273196 DOI: 10.1063/1.4891179] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
In this paper, we propose a new heuristic symbolic tool for unveiling chaotic and stochastic dynamics: the permutation spectrum test. Several numerical examples allow us to confirm the usefulness of the introduced methodology. Indeed, we show that it is robust in situations in which other techniques fail (intermittent chaos, hyperchaotic dynamics, stochastic linear and nonlinear correlated dynamics, and deterministic non-chaotic noise-driven dynamics). We illustrate the applicability and reliability of this pragmatic method by examining real complex time series from diverse scientific fields. Taking into account that the proposed test has the advantages of being conceptually simple and computationally fast, we think that it can be of practical utility as an alternative test for determinism.
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Affiliation(s)
- C W Kulp
- Department of Astronomy and Physics, Lycoming College, Williamsport, Pennsylvania 17701, USA
| | - L Zunino
- Centro de Investigaciones Ópticas (CONICET La Plata-CIC), C.C. 3, 1897 Gonnet, Argentina
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